<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div id="app">
    <p>{{cityId}}</p>
    <span>城市: </span>
    <select v-model="cityId">
        <option value="">未选择</option>
        <option :value="index" v-for="(city, index) in citys" :key="city.id">{{city.name}}</option>
    </select><br>
</div>
<script type="text/javascript" src="../js/vue.js"></script>
<script type="text/javascript">
    new Vue({
        el: '#app',
        data: {
            citys: [
                {id: 1, name: 'BJ'},
                {id: 2, name: 'SS'},
                {id: 3, name: 'SZ'}
            ],
            cityId: '1'
        },
    })
</script>
</body>
</html>